10 G passive optical networks (PON for short) include a 10 G bit/S Ethernet passive optical network (10 G EPON for short) and a 10 G bit passive optical network (XG PON for short). A standard organization defines that an optical line terminal (OLT for short) of a 10 G passive optical network uses an optical signal with wavelength of 1577 nm and a wavelength range from 1575 nm to 1580 nm. To satisfy the foregoing requirement, a laser of the 10 G passive optical network needs to use an electricity absorb modulate laser (EML for short).
An EML laser is usually required to work within a certain temperature range. Therefore, a thermal electric cooler (TEC for short) may generally be used to perform heating or cooling, so as to control an operating temperature of the EML laser.
An optical sub-assembly (OSA for short) or a transmitter optical sub-assembly (TOSA for short) that includes an EML laser may include a thermistor, a laser diode (LD for short), an electricity absorption (, EA for short) modulator, and a TEC, where the thermistor is configured to monitor an operating temperature inside the TEC, the LD is configured to send a single-longitudinal-mode laser with wavelength of 1577 nm, the EA modulator is configured to perform modulating and coding on an optical signal, and the TEC is configured to control operating temperatures of the LD and EA modulator, so as to control an operating temperature of the OSA.
Within a whole operating temperature range of the OSA or TOSA that includes the EML laser, a target control temperature of the thermal electric cooler TEC is a constant temperature. Specifically, when the OSA or TOSA works at a high temperature, the TEC needs to be cooled to the constant temperature; and when the OSA or TOSA works at a low temperature, the TEC needs to be heated to the constant temperature. Therefore, to ensure that the EML laser works at a constant temperature, the power consumption of the TEC is quite large.